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10#include <linux/fs.h>
11#include <linux/namei.h>
12#include <linux/xattr.h>
13#include <linux/security.h>
14#include <linux/cred.h>
15#include <linux/module.h>
16#include <linux/posix_acl.h>
17#include <linux/posix_acl_xattr.h>
18#include <linux/atomic.h>
19#include <linux/ratelimit.h>
20#include "overlayfs.h"
21
22static unsigned short ovl_redirect_max = 256;
23module_param_named(redirect_max, ovl_redirect_max, ushort, 0644);
24MODULE_PARM_DESC(ovl_redirect_max,
25 "Maximum length of absolute redirect xattr value");
26
27int ovl_cleanup(struct inode *wdir, struct dentry *wdentry)
28{
29 int err;
30
31 dget(wdentry);
32 if (d_is_dir(wdentry))
33 err = ovl_do_rmdir(wdir, wdentry);
34 else
35 err = ovl_do_unlink(wdir, wdentry);
36 dput(wdentry);
37
38 if (err) {
39 pr_err("overlayfs: cleanup of '%pd2' failed (%i)\n",
40 wdentry, err);
41 }
42
43 return err;
44}
45
46struct dentry *ovl_lookup_temp(struct dentry *workdir)
47{
48 struct dentry *temp;
49 char name[20];
50 static atomic_t temp_id = ATOMIC_INIT(0);
51
52
53 snprintf(name, sizeof(name), "#%x", atomic_inc_return(&temp_id));
54
55 temp = lookup_one_len(name, workdir, strlen(name));
56 if (!IS_ERR(temp) && temp->d_inode) {
57 pr_err("overlayfs: workdir/%s already exists\n", name);
58 dput(temp);
59 temp = ERR_PTR(-EIO);
60 }
61
62 return temp;
63}
64
65
66static struct dentry *ovl_whiteout(struct dentry *workdir)
67{
68 int err;
69 struct dentry *whiteout;
70 struct inode *wdir = workdir->d_inode;
71
72 whiteout = ovl_lookup_temp(workdir);
73 if (IS_ERR(whiteout))
74 return whiteout;
75
76 err = ovl_do_whiteout(wdir, whiteout);
77 if (err) {
78 dput(whiteout);
79 whiteout = ERR_PTR(err);
80 }
81
82 return whiteout;
83}
84
85
86int ovl_cleanup_and_whiteout(struct dentry *workdir, struct inode *dir,
87 struct dentry *dentry)
88{
89 struct inode *wdir = workdir->d_inode;
90 struct dentry *whiteout;
91 int err;
92 int flags = 0;
93
94 whiteout = ovl_whiteout(workdir);
95 err = PTR_ERR(whiteout);
96 if (IS_ERR(whiteout))
97 return err;
98
99 if (d_is_dir(dentry))
100 flags = RENAME_EXCHANGE;
101
102 err = ovl_do_rename(wdir, whiteout, dir, dentry, flags);
103 if (err)
104 goto kill_whiteout;
105 if (flags)
106 ovl_cleanup(wdir, dentry);
107
108out:
109 dput(whiteout);
110 return err;
111
112kill_whiteout:
113 ovl_cleanup(wdir, whiteout);
114 goto out;
115}
116
117int ovl_create_real(struct inode *dir, struct dentry *newdentry,
118 struct cattr *attr, struct dentry *hardlink, bool debug)
119{
120 int err;
121
122 if (newdentry->d_inode)
123 return -ESTALE;
124
125 if (hardlink) {
126 err = ovl_do_link(hardlink, dir, newdentry, debug);
127 } else {
128 switch (attr->mode & S_IFMT) {
129 case S_IFREG:
130 err = ovl_do_create(dir, newdentry, attr->mode, debug);
131 break;
132
133 case S_IFDIR:
134 err = ovl_do_mkdir(dir, newdentry, attr->mode, debug);
135 break;
136
137 case S_IFCHR:
138 case S_IFBLK:
139 case S_IFIFO:
140 case S_IFSOCK:
141 err = ovl_do_mknod(dir, newdentry,
142 attr->mode, attr->rdev, debug);
143 break;
144
145 case S_IFLNK:
146 err = ovl_do_symlink(dir, newdentry, attr->link, debug);
147 break;
148
149 default:
150 err = -EPERM;
151 }
152 }
153 if (!err && WARN_ON(!newdentry->d_inode)) {
154
155
156
157
158 err = -ENOENT;
159 }
160 return err;
161}
162
163static int ovl_set_opaque_xerr(struct dentry *dentry, struct dentry *upper,
164 int xerr)
165{
166 int err;
167
168 err = ovl_check_setxattr(dentry, upper, OVL_XATTR_OPAQUE, "y", 1, xerr);
169 if (!err)
170 ovl_dentry_set_opaque(dentry);
171
172 return err;
173}
174
175static int ovl_set_opaque(struct dentry *dentry, struct dentry *upperdentry)
176{
177
178
179
180
181
182 return ovl_set_opaque_xerr(dentry, upperdentry, -EIO);
183}
184
185
186static void ovl_instantiate(struct dentry *dentry, struct inode *inode,
187 struct dentry *newdentry, bool hardlink)
188{
189 ovl_dentry_version_inc(dentry->d_parent, false);
190 ovl_dentry_set_upper_alias(dentry);
191 if (!hardlink) {
192 ovl_inode_update(inode, newdentry);
193 ovl_copyattr(newdentry->d_inode, inode);
194 } else {
195 WARN_ON(ovl_inode_real(inode) != d_inode(newdentry));
196 dput(newdentry);
197 inc_nlink(inode);
198 }
199 d_instantiate(dentry, inode);
200
201 if (hardlink)
202 d_drop(dentry);
203}
204
205static bool ovl_type_merge(struct dentry *dentry)
206{
207 return OVL_TYPE_MERGE(ovl_path_type(dentry));
208}
209
210static bool ovl_type_origin(struct dentry *dentry)
211{
212 return OVL_TYPE_ORIGIN(ovl_path_type(dentry));
213}
214
215static int ovl_create_upper(struct dentry *dentry, struct inode *inode,
216 struct cattr *attr, struct dentry *hardlink)
217{
218 struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent);
219 struct inode *udir = upperdir->d_inode;
220 struct dentry *newdentry;
221 int err;
222
223 if (!hardlink && !IS_POSIXACL(udir))
224 attr->mode &= ~current_umask();
225
226 inode_lock_nested(udir, I_MUTEX_PARENT);
227 newdentry = lookup_one_len(dentry->d_name.name, upperdir,
228 dentry->d_name.len);
229 err = PTR_ERR(newdentry);
230 if (IS_ERR(newdentry))
231 goto out_unlock;
232 err = ovl_create_real(udir, newdentry, attr, hardlink, false);
233 if (err)
234 goto out_dput;
235
236 if (ovl_type_merge(dentry->d_parent) && d_is_dir(newdentry)) {
237
238 ovl_set_opaque(dentry, newdentry);
239 }
240
241 ovl_instantiate(dentry, inode, newdentry, !!hardlink);
242 newdentry = NULL;
243out_dput:
244 dput(newdentry);
245out_unlock:
246 inode_unlock(udir);
247 return err;
248}
249
250static struct dentry *ovl_clear_empty(struct dentry *dentry,
251 struct list_head *list)
252{
253 struct dentry *workdir = ovl_workdir(dentry);
254 struct inode *wdir = workdir->d_inode;
255 struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent);
256 struct inode *udir = upperdir->d_inode;
257 struct path upperpath;
258 struct dentry *upper;
259 struct dentry *opaquedir;
260 struct kstat stat;
261 int err;
262
263 if (WARN_ON(!workdir))
264 return ERR_PTR(-EROFS);
265
266 err = ovl_lock_rename_workdir(workdir, upperdir);
267 if (err)
268 goto out;
269
270 ovl_path_upper(dentry, &upperpath);
271 err = vfs_getattr(&upperpath, &stat,
272 STATX_BASIC_STATS, AT_STATX_SYNC_AS_STAT);
273 if (err)
274 goto out_unlock;
275
276 err = -ESTALE;
277 if (!S_ISDIR(stat.mode))
278 goto out_unlock;
279 upper = upperpath.dentry;
280 if (upper->d_parent->d_inode != udir)
281 goto out_unlock;
282
283 opaquedir = ovl_lookup_temp(workdir);
284 err = PTR_ERR(opaquedir);
285 if (IS_ERR(opaquedir))
286 goto out_unlock;
287
288 err = ovl_create_real(wdir, opaquedir,
289 &(struct cattr){.mode = stat.mode}, NULL, true);
290 if (err)
291 goto out_dput;
292
293 err = ovl_copy_xattr(upper, opaquedir);
294 if (err)
295 goto out_cleanup;
296
297 err = ovl_set_opaque(dentry, opaquedir);
298 if (err)
299 goto out_cleanup;
300
301 inode_lock(opaquedir->d_inode);
302 err = ovl_set_attr(opaquedir, &stat);
303 inode_unlock(opaquedir->d_inode);
304 if (err)
305 goto out_cleanup;
306
307 err = ovl_do_rename(wdir, opaquedir, udir, upper, RENAME_EXCHANGE);
308 if (err)
309 goto out_cleanup;
310
311 ovl_cleanup_whiteouts(upper, list);
312 ovl_cleanup(wdir, upper);
313 unlock_rename(workdir, upperdir);
314
315
316 d_drop(dentry);
317
318 return opaquedir;
319
320out_cleanup:
321 ovl_cleanup(wdir, opaquedir);
322out_dput:
323 dput(opaquedir);
324out_unlock:
325 unlock_rename(workdir, upperdir);
326out:
327 return ERR_PTR(err);
328}
329
330static int ovl_set_upper_acl(struct dentry *upperdentry, const char *name,
331 const struct posix_acl *acl)
332{
333 void *buffer;
334 size_t size;
335 int err;
336
337 if (!IS_ENABLED(CONFIG_FS_POSIX_ACL) || !acl)
338 return 0;
339
340 size = posix_acl_to_xattr(NULL, acl, NULL, 0);
341 buffer = kmalloc(size, GFP_KERNEL);
342 if (!buffer)
343 return -ENOMEM;
344
345 size = posix_acl_to_xattr(&init_user_ns, acl, buffer, size);
346 err = size;
347 if (err < 0)
348 goto out_free;
349
350 err = vfs_setxattr(upperdentry, name, buffer, size, XATTR_CREATE);
351out_free:
352 kfree(buffer);
353 return err;
354}
355
356static int ovl_create_over_whiteout(struct dentry *dentry, struct inode *inode,
357 struct cattr *cattr,
358 struct dentry *hardlink)
359{
360 struct dentry *workdir = ovl_workdir(dentry);
361 struct inode *wdir = workdir->d_inode;
362 struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent);
363 struct inode *udir = upperdir->d_inode;
364 struct dentry *upper;
365 struct dentry *newdentry;
366 int err;
367 struct posix_acl *acl, *default_acl;
368
369 if (WARN_ON(!workdir))
370 return -EROFS;
371
372 if (!hardlink) {
373 err = posix_acl_create(dentry->d_parent->d_inode,
374 &cattr->mode, &default_acl, &acl);
375 if (err)
376 return err;
377 }
378
379 err = ovl_lock_rename_workdir(workdir, upperdir);
380 if (err)
381 goto out;
382
383 newdentry = ovl_lookup_temp(workdir);
384 err = PTR_ERR(newdentry);
385 if (IS_ERR(newdentry))
386 goto out_unlock;
387
388 upper = lookup_one_len(dentry->d_name.name, upperdir,
389 dentry->d_name.len);
390 err = PTR_ERR(upper);
391 if (IS_ERR(upper))
392 goto out_dput;
393
394 err = ovl_create_real(wdir, newdentry, cattr, hardlink, true);
395 if (err)
396 goto out_dput2;
397
398
399
400
401 if (!hardlink &&
402 !S_ISLNK(cattr->mode) &&
403 newdentry->d_inode->i_mode != cattr->mode) {
404 struct iattr attr = {
405 .ia_valid = ATTR_MODE,
406 .ia_mode = cattr->mode,
407 };
408 inode_lock(newdentry->d_inode);
409 err = notify_change(newdentry, &attr, NULL);
410 inode_unlock(newdentry->d_inode);
411 if (err)
412 goto out_cleanup;
413 }
414 if (!hardlink) {
415 err = ovl_set_upper_acl(newdentry, XATTR_NAME_POSIX_ACL_ACCESS,
416 acl);
417 if (err)
418 goto out_cleanup;
419
420 err = ovl_set_upper_acl(newdentry, XATTR_NAME_POSIX_ACL_DEFAULT,
421 default_acl);
422 if (err)
423 goto out_cleanup;
424 }
425
426 if (!hardlink && S_ISDIR(cattr->mode)) {
427 err = ovl_set_opaque(dentry, newdentry);
428 if (err)
429 goto out_cleanup;
430
431 err = ovl_do_rename(wdir, newdentry, udir, upper,
432 RENAME_EXCHANGE);
433 if (err)
434 goto out_cleanup;
435
436 ovl_cleanup(wdir, upper);
437 } else {
438 err = ovl_do_rename(wdir, newdentry, udir, upper, 0);
439 if (err)
440 goto out_cleanup;
441 }
442 ovl_instantiate(dentry, inode, newdentry, !!hardlink);
443 newdentry = NULL;
444out_dput2:
445 dput(upper);
446out_dput:
447 dput(newdentry);
448out_unlock:
449 unlock_rename(workdir, upperdir);
450out:
451 if (!hardlink) {
452 posix_acl_release(acl);
453 posix_acl_release(default_acl);
454 }
455 return err;
456
457out_cleanup:
458 ovl_cleanup(wdir, newdentry);
459 goto out_dput2;
460}
461
462static int ovl_create_or_link(struct dentry *dentry, struct inode *inode,
463 struct cattr *attr, struct dentry *hardlink,
464 bool origin)
465{
466 int err;
467 const struct cred *old_cred;
468 struct cred *override_cred;
469 struct dentry *parent = dentry->d_parent;
470
471 err = ovl_copy_up(parent);
472 if (err)
473 return err;
474
475 old_cred = ovl_override_creds(dentry->d_sb);
476
477
478
479
480
481 if (origin) {
482 err = ovl_set_impure(parent, ovl_dentry_upper(parent));
483 if (err)
484 goto out_revert_creds;
485 }
486
487 err = -ENOMEM;
488 override_cred = prepare_creds();
489 if (override_cred) {
490 override_cred->fsuid = inode->i_uid;
491 override_cred->fsgid = inode->i_gid;
492 if (!hardlink) {
493 err = security_dentry_create_files_as(dentry,
494 attr->mode, &dentry->d_name, old_cred,
495 override_cred);
496 if (err) {
497 put_cred(override_cred);
498 goto out_revert_creds;
499 }
500 }
501 put_cred(override_creds(override_cred));
502 put_cred(override_cred);
503
504 if (!ovl_dentry_is_whiteout(dentry))
505 err = ovl_create_upper(dentry, inode, attr,
506 hardlink);
507 else
508 err = ovl_create_over_whiteout(dentry, inode, attr,
509 hardlink);
510 }
511out_revert_creds:
512 revert_creds(old_cred);
513 if (!err) {
514 struct inode *realinode = d_inode(ovl_dentry_upper(dentry));
515
516 WARN_ON(inode->i_mode != realinode->i_mode);
517 WARN_ON(!uid_eq(inode->i_uid, realinode->i_uid));
518 WARN_ON(!gid_eq(inode->i_gid, realinode->i_gid));
519 }
520 return err;
521}
522
523static int ovl_create_object(struct dentry *dentry, int mode, dev_t rdev,
524 const char *link)
525{
526 int err;
527 struct inode *inode;
528 struct cattr attr = {
529 .rdev = rdev,
530 .link = link,
531 };
532
533 err = ovl_want_write(dentry);
534 if (err)
535 goto out;
536
537 err = -ENOMEM;
538 inode = ovl_new_inode(dentry->d_sb, mode, rdev);
539 if (!inode)
540 goto out_drop_write;
541
542 inode_init_owner(inode, dentry->d_parent->d_inode, mode);
543 attr.mode = inode->i_mode;
544
545 err = ovl_create_or_link(dentry, inode, &attr, NULL, false);
546 if (err)
547 iput(inode);
548
549out_drop_write:
550 ovl_drop_write(dentry);
551out:
552 return err;
553}
554
555static int ovl_create(struct inode *dir, struct dentry *dentry, umode_t mode,
556 bool excl)
557{
558 return ovl_create_object(dentry, (mode & 07777) | S_IFREG, 0, NULL);
559}
560
561static int ovl_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
562{
563 return ovl_create_object(dentry, (mode & 07777) | S_IFDIR, 0, NULL);
564}
565
566static int ovl_mknod(struct inode *dir, struct dentry *dentry, umode_t mode,
567 dev_t rdev)
568{
569
570 if (S_ISCHR(mode) && rdev == WHITEOUT_DEV)
571 return -EPERM;
572
573 return ovl_create_object(dentry, mode, rdev, NULL);
574}
575
576static int ovl_symlink(struct inode *dir, struct dentry *dentry,
577 const char *link)
578{
579 return ovl_create_object(dentry, S_IFLNK, 0, link);
580}
581
582static int ovl_link(struct dentry *old, struct inode *newdir,
583 struct dentry *new)
584{
585 int err;
586 bool locked = false;
587 struct inode *inode;
588
589 err = ovl_want_write(old);
590 if (err)
591 goto out;
592
593 err = ovl_copy_up(old);
594 if (err)
595 goto out_drop_write;
596
597 err = ovl_nlink_start(old, &locked);
598 if (err)
599 goto out_drop_write;
600
601 inode = d_inode(old);
602 ihold(inode);
603
604 err = ovl_create_or_link(new, inode, NULL, ovl_dentry_upper(old),
605 ovl_type_origin(old));
606 if (err)
607 iput(inode);
608
609 ovl_nlink_end(old, locked);
610out_drop_write:
611 ovl_drop_write(old);
612out:
613 return err;
614}
615
616static bool ovl_matches_upper(struct dentry *dentry, struct dentry *upper)
617{
618 return d_inode(ovl_dentry_upper(dentry)) == d_inode(upper);
619}
620
621static int ovl_remove_and_whiteout(struct dentry *dentry,
622 struct list_head *list)
623{
624 struct dentry *workdir = ovl_workdir(dentry);
625 struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent);
626 struct dentry *upper;
627 struct dentry *opaquedir = NULL;
628 int err;
629
630 if (WARN_ON(!workdir))
631 return -EROFS;
632
633 if (!list_empty(list)) {
634 opaquedir = ovl_clear_empty(dentry, list);
635 err = PTR_ERR(opaquedir);
636 if (IS_ERR(opaquedir))
637 goto out;
638 }
639
640 err = ovl_lock_rename_workdir(workdir, upperdir);
641 if (err)
642 goto out_dput;
643
644 upper = lookup_one_len(dentry->d_name.name, upperdir,
645 dentry->d_name.len);
646 err = PTR_ERR(upper);
647 if (IS_ERR(upper))
648 goto out_unlock;
649
650 err = -ESTALE;
651 if ((opaquedir && upper != opaquedir) ||
652 (!opaquedir && ovl_dentry_upper(dentry) &&
653 !ovl_matches_upper(dentry, upper))) {
654 goto out_dput_upper;
655 }
656
657 err = ovl_cleanup_and_whiteout(workdir, d_inode(upperdir), upper);
658 if (err)
659 goto out_d_drop;
660
661 ovl_dentry_version_inc(dentry->d_parent, true);
662out_d_drop:
663 d_drop(dentry);
664out_dput_upper:
665 dput(upper);
666out_unlock:
667 unlock_rename(workdir, upperdir);
668out_dput:
669 dput(opaquedir);
670out:
671 return err;
672}
673
674static int ovl_remove_upper(struct dentry *dentry, bool is_dir,
675 struct list_head *list)
676{
677 struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent);
678 struct inode *dir = upperdir->d_inode;
679 struct dentry *upper;
680 struct dentry *opaquedir = NULL;
681 int err;
682
683 if (!list_empty(list)) {
684 opaquedir = ovl_clear_empty(dentry, list);
685 err = PTR_ERR(opaquedir);
686 if (IS_ERR(opaquedir))
687 goto out;
688 }
689
690 inode_lock_nested(dir, I_MUTEX_PARENT);
691 upper = lookup_one_len(dentry->d_name.name, upperdir,
692 dentry->d_name.len);
693 err = PTR_ERR(upper);
694 if (IS_ERR(upper))
695 goto out_unlock;
696
697 err = -ESTALE;
698 if ((opaquedir && upper != opaquedir) ||
699 (!opaquedir && !ovl_matches_upper(dentry, upper)))
700 goto out_dput_upper;
701
702 if (is_dir)
703 err = vfs_rmdir(dir, upper);
704 else
705 err = vfs_unlink(dir, upper, NULL);
706 ovl_dentry_version_inc(dentry->d_parent, ovl_type_origin(dentry));
707
708
709
710
711
712
713
714 if (!err)
715 d_drop(dentry);
716out_dput_upper:
717 dput(upper);
718out_unlock:
719 inode_unlock(dir);
720 dput(opaquedir);
721out:
722 return err;
723}
724
725static bool ovl_pure_upper(struct dentry *dentry)
726{
727 return !ovl_dentry_lower(dentry) &&
728 !ovl_test_flag(OVL_WHITEOUTS, d_inode(dentry));
729}
730
731static int ovl_do_remove(struct dentry *dentry, bool is_dir)
732{
733 int err;
734 bool locked = false;
735 const struct cred *old_cred;
736 bool lower_positive = ovl_lower_positive(dentry);
737 LIST_HEAD(list);
738
739
740 if (is_dir && (lower_positive || !ovl_pure_upper(dentry))) {
741 err = ovl_check_empty_dir(dentry, &list);
742 if (err)
743 goto out;
744 }
745
746 err = ovl_want_write(dentry);
747 if (err)
748 goto out;
749
750 err = ovl_copy_up(dentry->d_parent);
751 if (err)
752 goto out_drop_write;
753
754 err = ovl_nlink_start(dentry, &locked);
755 if (err)
756 goto out_drop_write;
757
758 old_cred = ovl_override_creds(dentry->d_sb);
759 if (!lower_positive)
760 err = ovl_remove_upper(dentry, is_dir, &list);
761 else
762 err = ovl_remove_and_whiteout(dentry, &list);
763 revert_creds(old_cred);
764 if (!err) {
765 if (is_dir)
766 clear_nlink(dentry->d_inode);
767 else
768 drop_nlink(dentry->d_inode);
769 }
770 ovl_nlink_end(dentry, locked);
771out_drop_write:
772 ovl_drop_write(dentry);
773out:
774 ovl_cache_free(&list);
775 return err;
776}
777
778static int ovl_unlink(struct inode *dir, struct dentry *dentry)
779{
780 return ovl_do_remove(dentry, false);
781}
782
783static int ovl_rmdir(struct inode *dir, struct dentry *dentry)
784{
785 return ovl_do_remove(dentry, true);
786}
787
788static bool ovl_type_merge_or_lower(struct dentry *dentry)
789{
790 enum ovl_path_type type = ovl_path_type(dentry);
791
792 return OVL_TYPE_MERGE(type) || !OVL_TYPE_UPPER(type);
793}
794
795static bool ovl_can_move(struct dentry *dentry)
796{
797 return ovl_redirect_dir(dentry->d_sb) ||
798 !d_is_dir(dentry) || !ovl_type_merge_or_lower(dentry);
799}
800
801static char *ovl_get_redirect(struct dentry *dentry, bool samedir)
802{
803 char *buf, *ret;
804 struct dentry *d, *tmp;
805 int buflen = ovl_redirect_max + 1;
806
807 if (samedir) {
808 ret = kstrndup(dentry->d_name.name, dentry->d_name.len,
809 GFP_KERNEL);
810 goto out;
811 }
812
813 buf = ret = kmalloc(buflen, GFP_KERNEL);
814 if (!buf)
815 goto out;
816
817 buflen--;
818 buf[buflen] = '\0';
819 for (d = dget(dentry); !IS_ROOT(d);) {
820 const char *name;
821 int thislen;
822
823 spin_lock(&d->d_lock);
824 name = ovl_dentry_get_redirect(d);
825 if (name) {
826 thislen = strlen(name);
827 } else {
828 name = d->d_name.name;
829 thislen = d->d_name.len;
830 }
831
832
833 if (thislen + (name[0] != '/') > buflen) {
834 ret = ERR_PTR(-EXDEV);
835 spin_unlock(&d->d_lock);
836 goto out_put;
837 }
838
839 buflen -= thislen;
840 memcpy(&buf[buflen], name, thislen);
841 tmp = dget_dlock(d->d_parent);
842 spin_unlock(&d->d_lock);
843
844 dput(d);
845 d = tmp;
846
847
848 if (buf[buflen] == '/')
849 break;
850 buflen--;
851 buf[buflen] = '/';
852 }
853 ret = kstrdup(&buf[buflen], GFP_KERNEL);
854out_put:
855 dput(d);
856 kfree(buf);
857out:
858 return ret ? ret : ERR_PTR(-ENOMEM);
859}
860
861static int ovl_set_redirect(struct dentry *dentry, bool samedir)
862{
863 int err;
864 const char *redirect = ovl_dentry_get_redirect(dentry);
865
866 if (redirect && (samedir || redirect[0] == '/'))
867 return 0;
868
869 redirect = ovl_get_redirect(dentry, samedir);
870 if (IS_ERR(redirect))
871 return PTR_ERR(redirect);
872
873 err = ovl_check_setxattr(dentry, ovl_dentry_upper(dentry),
874 OVL_XATTR_REDIRECT,
875 redirect, strlen(redirect), -EXDEV);
876 if (!err) {
877 spin_lock(&dentry->d_lock);
878 ovl_dentry_set_redirect(dentry, redirect);
879 spin_unlock(&dentry->d_lock);
880 } else {
881 kfree(redirect);
882 pr_warn_ratelimited("overlayfs: failed to set redirect (%i)\n",
883 err);
884
885 err = -EXDEV;
886 }
887 return err;
888}
889
890static int ovl_rename(struct inode *olddir, struct dentry *old,
891 struct inode *newdir, struct dentry *new,
892 unsigned int flags)
893{
894 int err;
895 bool locked = false;
896 struct dentry *old_upperdir;
897 struct dentry *new_upperdir;
898 struct dentry *olddentry;
899 struct dentry *newdentry;
900 struct dentry *trap;
901 bool old_opaque;
902 bool new_opaque;
903 bool cleanup_whiteout = false;
904 bool overwrite = !(flags & RENAME_EXCHANGE);
905 bool is_dir = d_is_dir(old);
906 bool new_is_dir = d_is_dir(new);
907 bool samedir = olddir == newdir;
908 struct dentry *opaquedir = NULL;
909 const struct cred *old_cred = NULL;
910 LIST_HEAD(list);
911
912 err = -EINVAL;
913 if (flags & ~(RENAME_EXCHANGE | RENAME_NOREPLACE))
914 goto out;
915
916 flags &= ~RENAME_NOREPLACE;
917
918
919 err = -EXDEV;
920 if (!ovl_can_move(old))
921 goto out;
922 if (!overwrite && !ovl_can_move(new))
923 goto out;
924
925 if (overwrite && new_is_dir && !ovl_pure_upper(new)) {
926 err = ovl_check_empty_dir(new, &list);
927 if (err)
928 goto out;
929 }
930
931 if (overwrite) {
932 if (ovl_lower_positive(old)) {
933 if (!ovl_dentry_is_whiteout(new)) {
934
935 flags |= RENAME_WHITEOUT;
936 } else {
937
938 flags |= RENAME_EXCHANGE;
939 }
940 } else if (is_dir && ovl_dentry_is_whiteout(new)) {
941 flags |= RENAME_EXCHANGE;
942 cleanup_whiteout = true;
943 }
944 }
945
946 err = ovl_want_write(old);
947 if (err)
948 goto out;
949
950 err = ovl_copy_up(old);
951 if (err)
952 goto out_drop_write;
953
954 err = ovl_copy_up(new->d_parent);
955 if (err)
956 goto out_drop_write;
957 if (!overwrite) {
958 err = ovl_copy_up(new);
959 if (err)
960 goto out_drop_write;
961 } else {
962 err = ovl_nlink_start(new, &locked);
963 if (err)
964 goto out_drop_write;
965 }
966
967 old_cred = ovl_override_creds(old->d_sb);
968
969 if (!list_empty(&list)) {
970 opaquedir = ovl_clear_empty(new, &list);
971 err = PTR_ERR(opaquedir);
972 if (IS_ERR(opaquedir)) {
973 opaquedir = NULL;
974 goto out_revert_creds;
975 }
976 }
977
978 old_upperdir = ovl_dentry_upper(old->d_parent);
979 new_upperdir = ovl_dentry_upper(new->d_parent);
980
981 if (!samedir) {
982
983
984
985
986
987
988 if (ovl_type_origin(old)) {
989 err = ovl_set_impure(new->d_parent, new_upperdir);
990 if (err)
991 goto out_revert_creds;
992 }
993 if (!overwrite && ovl_type_origin(new)) {
994 err = ovl_set_impure(old->d_parent, old_upperdir);
995 if (err)
996 goto out_revert_creds;
997 }
998 }
999
1000 trap = lock_rename(new_upperdir, old_upperdir);
1001
1002 olddentry = lookup_one_len(old->d_name.name, old_upperdir,
1003 old->d_name.len);
1004 err = PTR_ERR(olddentry);
1005 if (IS_ERR(olddentry))
1006 goto out_unlock;
1007
1008 err = -ESTALE;
1009 if (!ovl_matches_upper(old, olddentry))
1010 goto out_dput_old;
1011
1012 newdentry = lookup_one_len(new->d_name.name, new_upperdir,
1013 new->d_name.len);
1014 err = PTR_ERR(newdentry);
1015 if (IS_ERR(newdentry))
1016 goto out_dput_old;
1017
1018 old_opaque = ovl_dentry_is_opaque(old);
1019 new_opaque = ovl_dentry_is_opaque(new);
1020
1021 err = -ESTALE;
1022 if (d_inode(new) && ovl_dentry_upper(new)) {
1023 if (opaquedir) {
1024 if (newdentry != opaquedir)
1025 goto out_dput;
1026 } else {
1027 if (!ovl_matches_upper(new, newdentry))
1028 goto out_dput;
1029 }
1030 } else {
1031 if (!d_is_negative(newdentry) &&
1032 (!new_opaque || !ovl_is_whiteout(newdentry)))
1033 goto out_dput;
1034 }
1035
1036 if (olddentry == trap)
1037 goto out_dput;
1038 if (newdentry == trap)
1039 goto out_dput;
1040
1041 if (WARN_ON(olddentry->d_inode == newdentry->d_inode))
1042 goto out_dput;
1043
1044 err = 0;
1045 if (is_dir) {
1046 if (ovl_type_merge_or_lower(old))
1047 err = ovl_set_redirect(old, samedir);
1048 else if (!old_opaque && ovl_type_merge(new->d_parent))
1049 err = ovl_set_opaque_xerr(old, olddentry, -EXDEV);
1050 if (err)
1051 goto out_dput;
1052 }
1053 if (!overwrite && new_is_dir) {
1054 if (ovl_type_merge_or_lower(new))
1055 err = ovl_set_redirect(new, samedir);
1056 else if (!new_opaque && ovl_type_merge(old->d_parent))
1057 err = ovl_set_opaque_xerr(new, newdentry, -EXDEV);
1058 if (err)
1059 goto out_dput;
1060 }
1061
1062 err = ovl_do_rename(old_upperdir->d_inode, olddentry,
1063 new_upperdir->d_inode, newdentry, flags);
1064 if (err)
1065 goto out_dput;
1066
1067 if (cleanup_whiteout)
1068 ovl_cleanup(old_upperdir->d_inode, newdentry);
1069
1070 if (overwrite && d_inode(new)) {
1071 if (new_is_dir)
1072 clear_nlink(d_inode(new));
1073 else
1074 drop_nlink(d_inode(new));
1075 }
1076
1077 ovl_dentry_version_inc(old->d_parent, ovl_type_origin(old) ||
1078 (!overwrite && ovl_type_origin(new)));
1079 ovl_dentry_version_inc(new->d_parent, ovl_type_origin(old) ||
1080 (d_inode(new) && ovl_type_origin(new)));
1081
1082out_dput:
1083 dput(newdentry);
1084out_dput_old:
1085 dput(olddentry);
1086out_unlock:
1087 unlock_rename(new_upperdir, old_upperdir);
1088out_revert_creds:
1089 revert_creds(old_cred);
1090 ovl_nlink_end(new, locked);
1091out_drop_write:
1092 ovl_drop_write(old);
1093out:
1094 dput(opaquedir);
1095 ovl_cache_free(&list);
1096 return err;
1097}
1098
1099const struct inode_operations ovl_dir_inode_operations = {
1100 .lookup = ovl_lookup,
1101 .mkdir = ovl_mkdir,
1102 .symlink = ovl_symlink,
1103 .unlink = ovl_unlink,
1104 .rmdir = ovl_rmdir,
1105 .rename = ovl_rename,
1106 .link = ovl_link,
1107 .setattr = ovl_setattr,
1108 .create = ovl_create,
1109 .mknod = ovl_mknod,
1110 .permission = ovl_permission,
1111 .getattr = ovl_getattr,
1112 .listxattr = ovl_listxattr,
1113 .get_acl = ovl_get_acl,
1114 .update_time = ovl_update_time,
1115};
1116
